Abstract : This paper mainly introduces the hardware, software composition, working principle, and control method of the automatic control system for blast furnace slag granulation using the INBA method. Keywords : INBA control system 1. Overview : 1.1 Introduction : The INBA slag flushing system is widely used in blast furnace slag treatment. This system has a small footprint and saves water. This blast furnace has two INBA slag granulation systems installed in front of the furnace. Among them, INBA 1 slag granulation system is used for taps #1 and #2, and INBA 2 slag granulation system is used for tap #3. The two systems do not work simultaneously. 1.2 Main Equipment This system includes: the INBA water flushing system and the blast furnace water flushing circulating water pump station. The INBA system consists of two identical facilities. The main equipment consists of: granulation box, granulation tower, condensation tower, dewatering drum and rotating mechanism, buffer tank, hot water tank, collection tank, slag conveyor belt, various pumps, drainage circuit, compressed air, and cleaning circuit. Two INBA slag granulation systems share one cooling tower and circulating water pump room, slag stockpile, and water replenishment circuit. 2. System Hardware Configuration The control system hardware uses a Siemens SIMATIC S7 PLC. The basic configuration of the PLC system uses an S7-400 main unit and S7-400 series I/O modules. The PLC application program is designed and developed in the Step7 programming development environment. One industrial control computer is configured at the system operator station, serving as the human-machine interface for operation and monitoring. The control system HMI application program is designed and developed based on the industrial control configuration software WinCC. Communication between the operator station and the PLC is via industrial Ethernet. [align=center] Figure 1 System Hardware Configuration Diagram[/align] 3. System Control Methods 3.1 System Operation Methods The control of each device in the system adopts the following operation modes: on-site control and PLC centralized automatic control. ① PLC Centralized Automatic Operation Mode: This operation mode automatically completes the control (or action) of a process when the operation control conditions and process and equipment interlock conditions are met. The equipment's action commands or set values ​​are automatically controlled by the program according to the process interlock conditions. ② On-site Manual Operation Mode: This operation mode is used by personnel at the machine site for single-machine equipment maintenance and debugging. 3.2 System Control Method: Slag discharge begins 10-15 minutes after the taphole is opened. The hot slag is cooled by water spraying in the granulation box, blown into water slag, enters the granulation tower, and flows continuously into the INBA rotary drum under gravity through the distributor. After dewatering, it is transported to the water slag stockpile by a water slag conveyor belt. The flushing water filtered by the dewatering rotary drum is pumped to the cooling tower, cooled, and recycled. The consumed water is replenished by the water makeup system. The granulation tower generates a large amount of steam during the slag granulation process. This steam is condensed into water by spraying it into the upper condenser tower. The collected water then passes through a buffer tank and is pumped into a cooling tower for further cooling and reuse. Each water pump has two independent power supplies that can automatically switch between. The electric valve at the pump outlet is interlocked with the pump. To start the pump, start the pump first, then open the valve. To shut down the pump, close the valve first, then shut down the pump. 4. Control System Functions 4.1 Control System Functions The PLC control system can realize the following functions: ● Equipment safety interlock control ● Dewatering drum speed control ● Dewatering drum auxiliary control ● Slag conveying equipment interlock control ● Slag closed-loop circulating water control ● Slag granulation flushing pump control ● Pump group and valve equipment interlock control ● Operation data setting ● Data processing and transmission ● Equipment status monitoring ● Equipment fault handling 4.2 Human-Machine Interface System Functions The HMI system based on an industrial PC is the operating interface between the operator and the control system, mainly having the following functions: Displaying all steam pressure, flow rate, temperature, water pressure, and liquid level of the system; Process flow overview and equipment status display: The screen displays the process flow diagram and the working status of each piece of equipment; Alarm function: Divided into minor alarms and major alarms, the system displays the time of alarm occurrence, confirmation, and clearing; Distinguishing alarm event types and alarming according to their priority through real-time alarm information display, electric bell, screen alarm display, and alarm printing. Data processing and transmission; In addition, the HMI system has a computer system network communication diagram, PLC hardware configuration diagram and corresponding I/O status diagram to improve the maintainability of the system. The system screen operation is mainly carried out by mouse; the keyboard is only used for terminal data input. For safety reasons, some process-related operations must be confirmed by the operator. The system must perform data validity checks before receiving input from the operator. 5. Conclusion : After the system was put into operation, it was used well and ran stably, achieving the expected purpose and good results. About the author : Chen Ge: male, graduated from the Automation major of Wuhan University of Technology, now working at Taiyuan Iron and Steel Automation Research Institute, engineer. Contact information: Tel: (0351) 3017562; Address: Room 3, Automation Research Institute, Taiyuan Iron and Steel Company (030003) EMAIL: [email protected]